1. Field of the Invention
This invention relates to sustained flavor release compositions and more particularly to sustained flavor release compositions formed by appending appropriate hydrolyzable flavor groups onto polymer backbones.
2. Description of the Prior Art
It is known that with most flavored chewing gums the perception of flavor drops off sharply after a short initial period of chewing. It has also been noted that large amounts of the flavor incorporated into chewing gums are retained and never perceived by the chewer. Therefore, for chewing gum and many other applications, it would be advantageous if the release of flavors could be controllably released continuously and at a desirable level over a predetermined period of time.
One approach used to achieve improved sustained release of flavors has been to encapsulate the flavors prior to their incorporation into chewing gum. Corbin, U.S. Pat. No. 3,201,353, discloses the use of micro-inclusions containing flavors for chewing gums. in another patent, Pilotti, U.S. Pat. No. 3,011,949, it is taught that the controlled release of active ingredients from slab chewing gum can be achieved by coating solid particles of active flavor ingredients with a sugar solution, drying the coating, pulverizing the coated particles and mixing the pulverized material with the other constituents of slab chewing gum. Other techniques have been to use gelatin-coacervated flavors (U.S. Pat. No. 2,886,449), gelatin encapsulated flavors (U.S. Pat. No. 2,886,446), or gelatin metaphosphate encapsulated microdroplets of flavors (U.S. Pat. No. 2,886,444), within an all-enveloping mass of chewable base. Despite the amount of research done to control the release of flavors by encapsulation techniques, none of the methods previously known has proven successful to date.
A different technique for producing sustained release of flavors is disclosed in Heggie, U.S. Pat. No. 2,596,852. By this method, permanently flavored gums are formed by using gum bases formed from vinyl acetate copolymerized with vinyl unsaturated flavors. This technique, however, is severely limited by the number of vinyl unsaturated flavors available, and also because incorporation of flavors into the polymer chain tends to destroy the flavor producing characteristics of the flavor monomer. That is, once incorporated as part of the polymer via vinyl polymerization, the flavor molecule is so altered as to become an inseparable part of the polymer.
There is a great need, therefore, for new flavors capable of controllable sustained release.